Developmental biologists from several departments throughout Johns Hopkins University are submitting this application to acquire a COPAS Select Embryo Sorter for use in research and education in studies of Drosophila melanogaster and Caenorhabditis elegans. Historically, these organisms have had a significant impact on our understanding of human biology;a major experimental limitation, however, has been large-scale sorting of organisms of distinct genotypes. Although manual sorting techniques are successfully employed to obtain small samples, this procedure is too inefficient to isolate enough tissue for many applications, including microarray analyses, quantitative RT-PCR and biochemistry, or to use for large-scale genetic screens. Thus, we are applying for funds through the NIH Shared Instrumentation Grant Program (S10) to purchase, maintain and train individuals to use the COPAS Select Embryo Sorter from Union Biometrica. This is the only commercially available instrument of this kind. We have assembled a group of five major users, five minor users and a collaborator from across Johns Hopkins University who work in areas of developmental, molecular and computational biology, and whose research would be substantially enriched by the acquisition of this instrument. The users will focus on questions related to (1) deciphering the transcriptional networks controlling organ morphogenesis and physiology, (2) discovering how sexual dimorphism is controlled in both the germline and soma, (3) learning how germ cells are specified, maintained and, ultimately, differentiate (4) elucidating the signaling pathways controlling axonal targeting and sensory signaling, (5) understanding the cellular and molecular components mediating directed cell migration, (6) revealing the molecular constituents and events controlling myoblast fusion, and (7) deciphering the mechanisms of microRNA-mediated translational repression. This instrument will allow each user to carry out experiments that would otherwise be impossible and will also provide a mechanism for the cross-fertilization of ideas and the augmentation of research training and education. The embryo sorter will be housed in common space in the Cell Biology Department, adjacent to the laboratory of the PI on this grant. This site can be easily accessed by all of the users and is near several individuals who have experience using an earlier version of the instrument at other universities. Moreover, a research specialist in the PI's laboratory will be in charge of routine maintenance and training all new users. Public Health Relevance: Model organisms have become increasingly important in revealing the molecular and cellular mechanisms underlying normal development and disease. The studies included in this application are directed toward understanding key developmental events in organ and germ cell specification and differentiation in two experimental model organisms: the fruit fly Drosophila melanogaster and the nematode worm, Caenorhabditis elegans. Molecules and mechanisms discovered through these studies will provide therapeutic targets for treatment of diseases of the vasculature and kidneys, for reestablishing functional neuronal connections after traumatic injury, and for organ replacement therapy.